Synthesis, structure, and luminescence properties of arylpyridine-substituted terpyridine Zn(II) and Cd(II) complexes

Two terpyridine derivatives, 4′-(4-(pyridin-4-yl)phenyl)-[2,2′:6′,2″]terpyridine (L1) and 4′-(4′-(pyridin-4-yl)-[1,1′-biphenyl]-4-yl)-[2,2′:6′,2″]terpyridine (L2) have been synthesized by palladium-catalyzed cross-coupling reactions, and their metal complexes [Zn(L1)2](ClO4)2·2MeOH·CHCl3 (1) and [Cd(L2)2](ClO4)2·DMF·2.8H2O (2) characterized by single crystal X-ray crystallography and spectroscopic methods including electronic absorption and emission measurements. In the crystalline materials, both metal ions have the expected pseudo-octahedral N6 coordination environment and the lattice structures appear to be influenced by aromatic–aromatic interactions involving the heteroaryl tails and the pyridyl rings of the terpyridine units. In solution and in the solid state, the complexes display blue emission attributed to an intramolecular charge transfer transition.

Graphical abstractPolyarylterpyridine Zn(II) and Cd(II) complexes are described.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Two arylpyridine-substituted terpyridine derivatives and their metal complexes were synthesized. ► Both metal complexes revealed pseudo-octahedral structure. ► The lattice structures were influenced by aromatic–aromatic interactions. ► The photophysical properties of both complexes exhibited blue emission by ICT transition.